Tiêu chuẩn iso 00129 1 2004

Microsoft Word C029015e doc Reference number ISO 129 1 2004(E) © ISO 2004 INTERNATIONAL STANDARD ISO 129 1 First edition 2004 09 15 Technical drawings — Indication of dimensions and tolerances — Part[.]

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Reference numberISO 129-1:2004(E)

First edition2004-09-15

Technical drawings — Indication of dimensions and tolerances —

Part 1:

General principles

Dessins techniques — Indication des cotes et tolérances — Partie 1: Principes généraux

Copyright International Organization for Standardization

Reproduced by IHS under license with ISO

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Foreword iv

1 Scope 1

2 Normative references 1

3 Terms and definitions 2

3.1 Features 2

3.2 Lines of dimensioning 2

3.3 Dimensions 3

3.4 Arrangement of dimensions 3

4 Principles of dimensioning and of indication of tolerances 4

4.1 General principles 4

4.2 Positioning of dimensions 4

4.3 Units of dimensions 5

5 Elements of dimensioning 6

5.1 General 6

5.2 Dimension line 6

5.3 Terminators and origin indication 9

5.4 Extension line 9

5.5 Leader line 11

5.6 Dimensional values (basic dimensions) 11

5.7 Letters representing dimensions 14

5.8 Tabular dimensioning 14

6 Elements of indication of tolerances 15

6.1 General rules 15

6.2 Limit deviations 15

6.3 Limits of dimension 16

7 Indications of special dimensions 16

7.1 Arrangement of graphical and letter symbols with dimensional values 16

7.2 Diameters 17

7.3 Radii 18

7.4 Spheres 18

7.5 Arcs, chords and angles 18

7.6 Squares 20

7.7 Equally spaced and repeated features 20

7.8 Symmetrical parts 24

7.9 Indication of levels 25

7.10 Dimensions of out-of-scale represented features 25

7.11 Auxiliary dimensions 25

8 Arrangements of dimensions 25

8.1 General 25

8.2 Parallel dimensioning 25

8.3 Running dimensioning 26

8.4 Chain dimensioning 27

8.5 Coordinate dimensioning 28

8.6 Combined dimensioning 30

Annex A (normative) Relations and dimensions of graphical symbols 31

Bibliography 33

Copyright International Organization for Standardization Reproduced by IHS under license with ISO

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Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies

(ISO member bodies) The work of preparing International Standards is normally carried out through ISO

technical committees Each member body interested in a subject for which a technical committee has been

established has the right to be represented on that committee International organizations, governmental and

non-governmental, in liaison with ISO, also take part in the work ISO collaborates closely with the

International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2

The main task of technical committees is to prepare International Standards Draft International Standards

adopted by the technical committees are circulated to the member bodies for voting Publication as an

International Standard requires approval by at least 75 % of the member bodies casting a vote

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent

rights ISO shall not be held responsible for identifying any or all such patent rights

Subcommittee SC 1, Basic conventions

This part of ISO 129, together with ISO 129-2, cancels and replaces ISO 129:1985 and ISO 406:1987 of

which it constitutes a technical revision

ISO 129 consists of the following parts, under the general title Technical drawings — Indication of dimensions

and tolerances:

 Part 1: General principles

 Part 2: Mechanical engineering

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1

Technical drawings — Indication of dimensions and

ISO 128-20:1996, Technical drawings — General principles of presentation — Part 20: Basic conventions for

lines

ISO 128-22:1999, Technical drawings — General principles of presentation — Part 22: Basic conventions and

applications for leader lines and reference lines

ISO 128-30:2001, Technical drawings — General principles of presentation — Part 30: Basic conventions for

views

ISO 1000:1992, SI units and recommendations for the use of their multiples and of certain other units

ISO 3098-0:1997, Technical product documentation — Lettering — Part 0: General requirements

ISO 3098-5:1997, Technical product documentation — Lettering — Part 5: CAD lettering of the Latin alphabet,

numerals and marks

ISO 6284:1996, Construction drawings — Indication of limit deviations

ISO 6412-2:1989, Technical drawings — Simplified representation of pipelines — Part 2: Isometric projection ISO 6428:1982, Technical drawings — Requirements for microcopying

ISO 10209-2:1993, Technical product documentation — Vocabulary — Part 2: Terms relating to projection

methods

ISO/IEC 81714-1, Design of graphical symbols for use in the technical documentation of products — Part 1:

Basic rules

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3 Terms and definitions

For the purposes of this part of ISO 129, the following terms and definitions apply

NOTE The word geometrical may be deleted if no risk of misunderstanding occurs, hence, in this standard the word

“feature” will be used alone

3.1.2

feature of size

geometrical shape defined by a linear or angular dimension which is a size

[ISO 14660-1:1999, definition 2.2]

NOTE 1 The feature of size can be a cylinder, a sphere, two parallel opposite surfaces, a cone or a wedge

NOTE 2 In International Standards such as ISO 286-1 and ISO/R 1938-1, the meanings of the terms “plain workpiece” and “single features” are close to that of “feature of size”

line connecting information or requirements or a reference line with a feature or a dimension line

NOTE Adapted from ISO 128-22:1999

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distance between two features or the size of a feature of size

NOTE Linear and angular dimensions exist

NOTE 1 When no tolerance is indicated, the basic dimension is often called the dimensional value

NOTE 2 Unit of dimension should be linear or angular

NOTE 3 The tolerance limits and/or permissible deviations are applied to the basic dimension

3.3.3

linear dimension

linear distance between two features or the linear size of a feature of size

NOTE In mechanical engineering drawings, linear dimensions are classified in size, distances and radii (ISO/TR 14638)

3.3.4

angular dimension

the angle between two features or the angle of an angular feature of size

NOTE In mechanical engineering drawings, angular dimensions are classified in angular size and angular distances (ISO/TR 14638)

method of dimensioning where single dimensions are arranged in a row

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3.4.2

coordinate dimensioning

method of dimensioning from a reference feature in a coordinate system

EXAMPLE Cartesian or polar coordinates, see ISO 10209-2

All dimensions, graphical symbols and annotations shall be indicated such that they can be read from the

bottom or right-hand side (main reading directions) of the drawing

Dimensions are one of several types of geometrical requirements, which may be used to define a feature or

component clearly and unambiguously Other types of geometrical requirements, which most often are

needed to obtain an unambiguous definition of the feature (e.g in mechanical engineering) are geometrical

tolerances (form, orientation, location and run-out), surface texture requirements and requirements for corners

NOTE In the construction engineering, tolerances are often given in separate documents

All dimensional information shall be complete and shown directly on a drawing unless this information is

specified in related associated documentation

Each feature or relation between features shall be dimensioned only once

Where all linear dimensions are expressed in the same unit, the unit symbol may be omitted, provided the

drawing or associated documentation carries a statement of the unit used

4.2 Positioning of dimensions

Dimensions should be placed on that view or section which shows the relevant feature(s) most clearly (see

Figure 1)

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Figure 1

Where several features or objects are depicted in close proximity, their relative dimensions should be grouped, together, separately, for ease of reading (see Figure 2)

Figure 2

4.3 Units of dimensions

Dimensions shall be indicated using only one unit of dimension Where a variety of units of dimension are used within one document, they shall be clearly indicated

For dimensions, SI units shall be used; see ISO 1000 or other International Standards relevant for SI units Limit deviations shall be expressed in the same unit as the basic dimension

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5 Elements of dimensioning

5.1 General

The elements of dimensioning are extension lines, dimension lines, leader lines, terminators, indication of origins and dimensional values (basic dimensions) Various elements of dimensioning are illustrated in Figure 3; the origin circle is indicated in Figures 62 to 64

Dimension lines shall be drawn with a continuous narrow line according to ISO 128-20

Dimension lines shall be indicated in the case of

 linear dimensions parallel to the length to be dimensioned (see Figure 4),

 angular dimensions or dimensions of an arc as a circular arc around the vertex of the angle or the centre

of the arc (see Figures 5 and 6), and

 radii generated from the geometrical centre of the radius (see Figure 6)

Where space is limited, dimension lines may be indicated with extensions and reversed arrowheads (see Figure 1)

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Figure 4 Figure 5 Figure 6

Where the feature is shown broken, the corresponding dimension line shall be shown unbroken (see Figure 7)

Figure 7

Intersection of dimension lines with any other line should be avoided, but where intersection is unavoidable they shall be shown without a break (see Figure 8)

Figure 8

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Dimension lines may be shown not in full, when

 dimensions of diameters are indicated (see Figure 9),

 only a part of a symmetrical feature is drawn in a view or section (see Figures 55 and 56),

 a feature is drawn half in a view and half in a cut (see Figure 9),

 the reference feature for dimensioning is not on the drawing sheet and there is no need for its indication (see Figure 40 R62),

 referring to grids on construction drawings (see Figure 10)

Figure 9

Figure 10

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5.3 Terminators and origin indication

5.3.1 The size ratios of the terminators illustrated in Figure 11 and of the origin circle illustrated in Figure 12

are given in Annex A

5.3.2 The termination of dimension lines shall be according to one of the representations shown in

Figure 11

a) Arrowhead, closed and filled 30° b) Arrowhead, closed 30° c) Arrowhead, open 30°

d) Arrowhead, open 90° e) Oblique stroke f) Point (used only if no place for

arrowhead; the oblique stroke may

also be used) Figure 11

5.3.3 The indication of the origin of the dimension line shall be as shown in Figure 12

Figure 12

5.4 Extension line

Extension lines shall be drawn as continuous narrow lines according to ISO 128-20

Extension lines shall extend approximately 8 times the line width beyond the respective dimension line

Extension lines should be drawn perpendicular to the corresponding physical length (see Figures 4 and 5, 7 to

9 and 13)

It is permissible to have a gap (approximately 8 times the line width) between the feature and the beginning of the extension line in certain technical fields (see Figure 14)

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The extension lines may be drawn obliquely, but parallel to each other (see Figure 15)

Figure 15

Intersecting projected contours of outlines shall extend approximately 8 times the line width beyond the point

of intersection (see Figure 16)

Figure 16

In the case of projected contours of transitions and similar features, the extension lines apply at the point of intersection of the projection lines (see Figure 17)

Figure 17

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Extension lines may be interrupted if their continuation is unambiguous (see Figures 18 and 19) In the case of angular dimensions, the extension lines are the extensions of the angle legs (see Figure 19)

Dimensional values shall be indicated on drawings in characters of sufficient size to ensure complete legibility

on the original drawing as well as on reproductions made from microfilms (see ISO 6428) Lettering B vertical according to ISO 3098-0 is recommended

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5.6.2 Positions of dimensional values

Dimensional values shall be placed parallel to their dimension line and near the middle of and slightly above that line (see Figures 21 and 22 and Annex A)

Dimensional values shall be placed in such a way that they are not crossed or separated by any line

Figure 21

Figure 22

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For exceptions, see 5.6.3

Values on oblique dimension lines shall be oriented as shown in Figure 23

Values of angular dimensions shall be oriented as shown in Figure 24

5.6.3 Special positions of dimensional values

The position of dimensional values frequently needs adaptation to different situations:

a) dimensional values can be above the extension of the dimension line beyond one of the terminators, if space is limited (see Figure 25);

b) dimensional values can be shown on a reference line, and attached to the dimension line by a leader line, terminating on the dimension line that is too short for the dimensional value to be indicated in the usual way between the extension lines (see Figure 25);

Figure 25

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c) dimensional values can be placed above a horizontal extension of a dimension line where space does not allow placement parallel to the dimension line (see Figure 26);

Figure 26

d) in running dimensioning, the values shall be indicated near the arrowhead (see Figures 63 and 64)

5.7 Letters representing dimensions

Letters may be used to represent dimensional values and these shall be defined on the same drawing or in associated documentation (see Figure 27)

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6 Elements of indication of tolerances

is one size smaller than the lettering height of the basic dimension, but not smaller than 2,5 mm

Depending on the field of application, the tolerances of dimensions may be indicated by

 symbols of the tolerance classes (ISO 2768-1 and ISO 2768-2),

 limit deviation (see 6.2),

 limits of dimension (see 6.3), or

Limit deviations, according to ISO 286-1, shall be indicated either by indicating the upper deviation above the lower deviation (see Figures 28 and 30), or by indicating the upper deviation before the lower deviation on the same line, separated from it by a slash (see Figure 29)

If one of the two limit deviations is zero, this shall be expressed by the digit zero (see Figure 30)

If the tolerance is symmetrical in relation to the basic dimension, the limit deviation shall be indicated once only, preceded by the sign “±” (see Figure 31)

Figure 28 Figure 29 Figure 30 Figure 31

Tiêu đề	Indication of Dimensions and Tolerances
Trường học	International Organization for Standardization
Chuyên ngành	Technical Drawings
Thể loại	international standard
Năm xuất bản	2004
Thành phố	Geneva

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